| High performance liquid chromatography?HPLC?is an efficient,rapid and practical modern separation and analysis technology.The separation of complex samples mainly depend on chromatography separation technology.With the development of modern society and science and technology,it becomes a great challenge for chromatographers to get an efficient and rapid separation of complex samples.Columns packed with core-shell particles have the advantage of high column efficiency,high resolution and low back pressure,as a result,it has more and more become an ideal tool for the ultra-fast liquid chromatographic analysis and has been applied to the efficient separation and analysis of complex samples successfully.Polymerization-induced colloidal coacervation?PICA?and Template method are the two main methods to prepare core shell particles.However,these two mentioned methods all have their drawbacks.It tends to generate the problems of agglomeration and secondary nucleation in the process of preparation of shell particles by using PICA,whereas the pore size of shell particle prepared by template method is too small to be applied in the chromatography separation,which leads to a further process of the enlargement of its pore size.Therefore,in order to solve the above problems,this paper has optimized a series of experimental conditions for preparation of SiO2@SiO2 core-shell microspheres by PICA and conducted a small-scale amplification preparation of shell particles.We can further use template method which uses the synergistic effect of two kinds of template agents and use it to conduct the rapid separation and analysis of small molecules and proteins.1.Introduction:This chapter gives a comprehensive review on the advantage,preparation method and application of core-shell silica microspheres.2.Preparation of SiO2@SiO2 core-shell microspheres by polymerization-induced colloidal condensation method:On the basis of the previous work of our research group,SiO2@SiO2core-shell microspheres were prepared by small-scale amplification using PICA method.Monodisperse SiO2@SiO2 core-shell microspheres with uniform morphology and particle size were prepared by adjusting the factors of pH,temperature,concentration of formaldehyde and urea and stirring rate so as to solve the problems such as secondary nucleation,agglomeration and uneven coating in the preparation process of SiO2@SiO2 microspheres.In addition,the effect of the compactness of the shell on the mechanical strength of the core-shell microspheres as well as the calcination temperature on the particle surface morphology were investigated.Controllable preparation of SiO2@SiO2 core shell particles with different shell thickness and pore size was achieved by changing different reaction time and different size of silica sol nanoparticles at the same time with a constant mass ratio of core and shell.The maximum yield can reached 10 g.The chromatographic properties of SiO2@SiO2 core-shell microspheres prepared by amplification were also investigated.The core-shell chromatographic column SiO2@SiO2-C18 under reversed-phase chromatographic mode can achieve rapid separation of small molecules and proteins.SiO2@SiO2-C18 core-shell microspheres also applied to the separation and analysis of BSA/Hela cells/mouse liver tissue cells enzymatic hydrolysate.Comparisons of the results with full-porous silica-C18 capillary column showed that the more proteins and polypeptides can be analyzed using the prepared SiO2@SiO2-C18 core-shell capillary column,which indicates that the prepared core-shell column has good application value in the separation and analysis of proteins and polypeptides in complex proteomics samples.3.Preparation of SiO2@SiO2 core-shell microspheres by two-phase method:SiO2@SiO2core-shell microspheres with radial channel structure were prepared by two-phase method.This chapter explores the influence of reaction time,temperature,stirring speed,ODA dosage and other factors on the secondary nucleation during the preparation process,but the influence of the ratio of core to shell material on the shell thickness as well.Microporous core-shell microspheres with radial channels were prepared using toluene as organic solvent under optimal conditions.4.Application of SiO2@SiO2 core-shell microspheres in rapid separation of small molecules:SiO2@SiO2 core-shell microspheres prepared by two-phase method were modified with octadecyltrichlorosilane to prepare the reverse phase liquid chromatography.The performance of core-shell column for the separation of 6 kinds of alkyl benzene,5 kinds of homologues of aromatic alcohols and 7 kinds of proteins was studied under reversed-phase chromatography mode.The results showed that the prepared SiO2@SiO2 core-shell chromatographic column can achieve a rapid separation of small solutes molecule whose theoretical plates number can reach 160,000/m and large molecule.On the basis of above results,we can conclude that the prepared SiO2@SiO2 core-shell column has an excellent column efficiency and separation ability.Thus,the SiO2@SiO2 core-shell column can be used for rapid separation of small and large molecules. |
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